Method and apparatus for passing lines through conduits



P 1962 J. c. HAMRICK 3,052,451

METHOD AND APPARATUS FOR PASSING LINES THROUGH CONDUITS Filed Nov. 18, 1958 2 Sheets-Sheet 1 g INVENTOR: JAnEs CHAMmcK BY @FMLAXM 1 ATTORNEYS J. C. HAMRICK Sept. 4, 1962 METHOD AND APPARATUS FOR PASSING LINES THROUGH CONDUITS Filed NOV- 18, 1958 2 Sheets-Sheet 2 0 w A J mK m R w A W H C S E m J NJ \1 1 6. N 2

BY Q QMMMW ATTORNEYS This invention relates to a method and apparatus for passing a guide line through a conduit by utilizing a cartridge projectile to which is attached a trailing line package adapted to pay out the guide line. After the guide line has been passed through the conduit, one of its ends may be connected to a relatively rigid line or similar elongated article-such as an electrical cable or conductor, a lengthy thermosensitive element, etc.which, because of its particular physical characteristics, cannot be intially passed through the conduit without experiencing great difiiculty. By pulling the guide line, the relatively rigid line or similar elongated article attached thereto may be drawn into the conduit for installation therewithin.

The present method and apparatus constitute an improvement over the invention disclosed in co-pending United States patent application 674,930 filed July 29, 1957, now Patent Number 2,930,584, of which I am a joint inventor. As part of the novel apparatus herein disclosed, I contemplate the use of several attachments with a hand tool or gun which is adapted to launch or fire the cartridge projectile, the attachments facilitating the passage of the cartridge projectile and the accompanying line package through a conduit.

I am aware that the practice of passing a guide line through a conduit for subsequently drawing an electrical cable or the like therethrough has been previously attempted. Such attempts have invariably required the use of a projectile to one end of which a guide line is attached, the projectile being large enough in diameter to provide a seal with the bore-defining wall surface of the conduit through which the guide line is to be passed. Pneumatic or hydraulic pressure must then be employed to force the projectile and the guide line attached thereto through the conduit. The practice of such a method not only requires a readily available source of pressure, but is likely to be relatively slow and inefficient. To maintain an effective propelling pressure behind the projectile, the conduit must be leak-proof and without variations in its bore diameter, while the projectile itself must be of a specific size with respect to each individual conduit to insure the formation of a good seal between the projectile and the bore-defining wall surface of the conduit. An extremely long conduit or one possessing a number of angular bends therein further adds to the difliculties in practicing the aforesaid method by requiring increased amounts of propelling pressure as well as complicating the problem of maintaining a seal between the projectile and the bore-defining Wall surface of the conduit.

Moreover, where the distance to be traveled through the conduit is relatively long and where the conduit is formed with numerous angular bends therein, or a combination of these two factors, the problem of frictional resistance created by the pulling of the guide line through the conduit by the projectile is accentuated. The length of the conduit and the number of bends present therein add to the frictional resistance created by the guide line as it is pulled through the conduit by the projectile, thereby placing still greater demands upon the source of propelling pressure.

In co-pending United States patent application 674,930, now Patent Number 2,930,584, referred to previously,

atent there is disclosed the concept of utilizing a cartridge projectile, which discharges a gaseous substance to develop a forward thrust, around which is coiled a line adapted to be unwound as the cartridge projectile travels through a conduit to lay the line therethrough. While this method of passing a guide line through a conduit has proved superior to the practices previously in use in that the frictional resistance developed by the line is negligible and no independent source of propelling pressure is necessary, it has been determined that where the runs to be made by the cartridge projectile involve long distances and many angular bends, improved results can be obtained by attaching a trailing line package to the cartridge projectile for unwinding as the cartridge projectile carries the line package through the conduit.

In launching a cartridge projectile containing a gaseous propellant into a conduit for the purpose of passing a guide line therethrough, additional problems can be created if the cartridge projectile is not properly alined with the end of the conduit which it is adapted to enter.

One of the objects of this invention resides in an improved method of passing a guide line through a conduit for subsequently pulling another line, cable or the like through the conduit by the guide line. The improved method involves the attachment of a line package to the trailing end of a cartridge projectile containing a gaseous propellant, wherein the line package accompanies the cartridge projectile as it travels through the conduit, while unwinding the line in the conduit as it moves therethrough. Through the use of this improved method, the frictional resistance hindering the onward movement of the cartridge projectile which is developed by the line as it is unwound in the conduit from the line package is greatly reduced, enabling the cartridge projectile to obtain the maximum benefit from the forward thrust imparted thereto by the gaseous propellant contained therein. This improved method is therefore especially desirable where long conduit runs are necessary and where a plurality of angular bends. are formed in the conduit through which a guide line is to be passed for subsequent installation of a relatively rigid elongated article, such as an electrical cable.

Another object of this invention is to provide a novel apparatus to be used in practicing the aforesaid improved method for passing a guide line through a conduit wherein a trailing line package accompanies a cartridge projectile to which it is attached as the cartridge projectile travels through the conduit while line from the line package is unwound in the length of the conduit. The apparatus includes a hand tool or gun having a launching attachment releasably secured thereto, the launching attachment receiving the cartridge projectile and the line package in respective barrel members thereof. The line package is attached to the rear end of the cartridge projectile and the trailing end of the line in the line package is attached to a stationary object adjacent an end of the conduit. The apparatus further includes a conduit entrance adapter in the form of a funnel disposed about the forward end of the launching attachment in surrounding relation to the cartridge projectile and the line package received by the launching attachment, the entrance adapter tapering outwardly of the hand tool for insertion in the end of the conduit through which the guide line is to be passedto insure the successive but separate introduction of the cartridge projectile and the trailing line package attached thereto into the end of the conduit for proper flight therethrough, whereupon the line from the line package is unwound in the length of the conduit, following the firing of the hand tool to actuate the cartridge projectile, in response to movement of the cartridge projectile carrying the attached trailing line package away from the stationary object.

Another object of this invention is to provide a novel launching attachment to be secured to the barrel of a hand tool or gun for firing a cartridge projectile containing a gaseous propellant, the launching attachment having bores for containing the cartridge projectile and a line package attached thereto respectively and means to releasably retain the cartridge projectile and the line package in the bores to prevent the same from being accidentally dislodged therefrom.

It is another object of this invention to provide a conduit entrance adapter of resilient insulative material in the form of a funnel surrounding the launching attachment which is secured to the barrel of a hand tool or gun adapted to fire a cartridge projectile having a line package attached thereto. The funnel includes a tubular tapered choke portion for insertion in the end of the conduit through which the cartridge projectile is to be fired, the choke portion of the funnel automatically alining the cartridge projectile and the accompanying line package for proper flight through the conduit.

It is another object of this invention to provide a cartridge projectile with a line package attached to the trailing end thereof, the line package comprising a line wound in a roll and having one end trailing from the rear end of the roll which is adapted to be attached to an independent object for unwinding the line from the roll in response to movement of the cartridge projectile carrying the line package away from the object.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIGURE 1 is a side elevational view of a hand tool or gun showing a cartridge projectile and a line package within a launching attachment secured to the barrel of the gun, preparatory to firing the gun for launching the cartridge projectile, portions of the gun being broken away to show the firing mechanism;

FIGURE 2 is an enlarged exploded perspective view of the launching attachment and the cartridge projectile and line package receivable therein together with a fragmentary portion of the forward end of the barrel of the gun shown in FIGURE 1, the line package being partially broken away;

FIGURE 3 is a transverse sectional view of the launching attachment taken along line 33 in FIGURE 2;

FIGURE 4 is a reduced side elevational view similar to that shown in FIGURE 1, but showing a conduit entrance adapter or funnel installed about the launching attachment;

FIGURE 5 is a greatly reduced side elevational View showing the gun applied to a conduit wherein the funnel is inserted in one end of the conduit, the conduit being partially broken away to show the cartridge projectile and the trailing line package as they travel through the conduit;

FIGURE 6 is an enlarged perspective view of the conduit entrance adapter or funnel shown in FIGURE 4;

FIGURE 7 is a fragmentary enlarged longitudinal sectional view of the funnel taken along line 7-7 in FIG- URE 6;

FIGURE 8 is an enlarged elevational view, illustrating the cartridge projectile and the trailing line package as they travel through a conduit shown in longitudinal section, with a cartridge catcher, partially broken away, disposed about the end of the conduit;

FIGURE 9 is a fragmentary longitudinal sectional view of the restrictor portion of the cartridge catcher showing a cartridge projectile trapped therein; and

FIGURE 10 is an enlarged fragmentary vertical sectional view through a conduit of relatively large diameter and illustrating a cartridge projectile traveling therethrough, the cartridge projectile having a nose cone, partially broken away, attached to its forward end to increase the efiective length thereof.

Referring more specifically to the drawings, in FIG- URE 1, there is illustrated a hand tool or gun 10 having a firing mechanism which includes a trigger 11 for releasing a spring-urged plunger 12 adapted to puncture the rear end of a cartridge projectile 13 containing a gaseous propellant substance, such as compressed carbon dioxide, for a purpose to be subsequently described. The gun 10 includes a barrel 14 having a central bore in which the plunger 12 is received. The plunger 12 is generally cylindrical, having one end which extends beyond and to the rear of the barrel 14 of the gun 10. A cocking head 15 is formed on the end of the plunger 12 disposed rearwardly of the barrel 14. An enlarged collar 16 is rigidly affixed about the plunger 12 at a medial location thereon within the barrel 14, the collar 16 providing a rearwardly disposed shoulder for seating one end of a compression spring 17 thereagainst. The opposite end of the compression spring 17 is seated against a plate 18 closing the rear end of the barrel 14 and being suitably apertured to permit the plunger 12 to extend therethrough beyond the barrel 14.

In addition to the trigger 11, the firing mechanism includes a latch bar 19, shown in phantom lines in FIGURE 1, the latch bar 19 having a central pivot point and'a flanged end 20 adapted to be seated against the forward shoulder defined by the collar 16 rigidly secured about the plunger 12. The opposite end of the latch bar 19 is lightly disposed atop a tripping lever arm 21 formed integrally with the trigger 11 which is adapted to be moved in an upwardly directed arc, upon the trigger 111 being pulled, to pivot the latch bar 19 about its central pivot point, thereby moving the flanged end 20 downwardly and releasing the collar 16 from engagement with the flanged end 20 of the latch bar 19. The coiled spring 17 having been placed under a high degree of compression is thereby permitted to expand upon the release of the collar 16 by the latch bar 19 to force the plunger 12 forwardly in the barrel 14 of the gun 10. It will be observed that the forward end of the plunger 12 is provided with a firing pin 22 adapted to puncture the rear end of the cartridge projectile 13 for releasing the gaseous substance contained therein to exert a forward thrust thereto.

The peripheral surface of the collar 16 is preferably tapered in a rearward direction to facilitate the cooking of the gun 10 after it has been fired. The gun 10 may be cocked for subsequent re-firing by grasping the cocking head 15 and pulling the same rearwardly which causes the tapered peripheral surface of the collar 16 to ride past the flanged end 20 of the latch bar 19 while the spring 17 is compressed between the collar 16 and the plate 1 8. When the collar 16 has been drawn past the flanged end 20 of the latch bar 19, the flanged end 20 is restored to abutting relationship with the forward shoulder of the collar 16 to hold the plunger 12 in cocked position for release upon the trigger 11 being pulled.

A line package 30 is attached to the rear end of the cartridge projectile 13 by means of a split ring circlet 31 through which is entwined a loop 32 of line L extending forwardly from the line package 30. These two elements, the cartridge projectile 13 and the line package 30, are disposed in a launching attachment 35 releasably secured to the forward end of the barrel 14 of the gun 10 in a manner to be subsequently described. The launching attachment 35 comprises upper and lower elongate barrel members 36, 3-7 secured together in parallel relationship. The upper and lower barrel members 36, 37 are each provided with a longitudinal bore extending therethrough and have means thereon for releasably retaining the cartridge projectile 13 and the line package 30 therein, respectively. This retaining means takes the form of a leaf spring 40 which is secured at one end to the external surface of the corresponding barrel member 36 or 37 by suitable means, such as a screw S. The opposite free end of the leaf spring 40 is provided with a projection or lug 4-1 thereon extending inwardly through an aperture provided in the wall of the respective barrel member. This structural arrangement is shown most clearly in FIGURE 3, it being apparent that the projections 41 on the leaf springs 40 which protrude within the longitudinal bores formed in the upper and lower barrel members 36, 37 respectively are adapted to resiliently engage the cartridge projectile 13 and the line package for releasably retaining these elements within the launching attachment preparatory to the firing of the gun It? for launching the cartridge projectile 13.

The means for releasably securing the launching attachment 35 on the barrel 14 of the gun 10, as shown in the drawings, comprises a reduced end portion 14a on the barrel 14 which has an L-shaped or bayonet slot 42 formed in the forward end thereof. The reduced end Portion 14a of the barrel 14 is telescopically received within the bore of the upper barrel member 36. Therefore, to install the launching attachment 35 on the barrel 14 of the gun 10, the bayonet slot 42 formed on the reduced end portion 14a of barrel 14 is alined with the screw S securing the leaf spring to the external surface of the upper barrel member 36, it being noted in FIGURE 3 that the screw S protrudes within the longitudinal bore formed in the upper barrel member 36. Upon the screw S being guided along the bayonet slot 42 to the closed end thereof, the launching attachment 35 is secured to the barrel 14 of the gun 10.

The line package 30 comprises a line L wound in an elongated cylindrical roll 45 and sheet material, such as a paper wrapping 46, covering the cylindrical roll 45. A suitable coating of adhesive substance or glue is preferably provided on the interior surface of the paper wrapping 46 to firmly secure the outermost winding of line L comprising the elongated cylindrical roll 45 to the paper Wrapping 46. The adhesion between the paper wrapping 46 and the outermost winding of the L aids in maintaining the shape of the line package 30 intact. It will be observed that the rear end of the cylindrical roll 45 is unobstructed by the paper wrapping 46, thereby permitting one end of the line L to trail outwardly of the cylindrical roll 45 from substantially the longitudinal axis thereof. The forward end of the cylindrical roll 45 is sealed by the paper wrapping 46 which includes a twisted portion 47 covering the forward end of the cylindrical roll 45. The opposite end of the line L is turned upon itself to form the aforesaid loop 32 entwined through the circlet 3 1 on the rear end of the cartridge projectile 13, the loop 32 extending through the twisted portion 47 of the paper wrapping 46 which is adhesively secured thereto. The free end of the loop 32 is imprisoned within the line package 30 'by adhesive securement to the interior surface of the paper wrapping 46. Upon the rear end of the cartridge projectile 13 being punctured by the firing pin 22 of the plunger 12, the cartridge projectile 13 is thrust forwardly by the escape of gas from its rear end and carries therewith the trailing line package 30 which is attached thereto by the loop 32 formed in the line L of the cylindrical roll 45.

To insure the proper alinement of the launching attachment 35 containing the cartridge projectile 13 and the line package 30 with a conduit C through which the line L is to be passed, an entrance adapter or funnel 60 is provided. The funnel 60 includes a hollow body portion 61 having an open end for reception of the launching attachment 35 therewithin. The hollow body portion 61 comprises substantially arcuately curved top and bottom walls which merge with side walls substantially parallel with respect to each other. As will be most apparent in FIGURE 4, the bottom wall of the body portion 61 flares inwardly from the open end of the body portion 61 which receives the launching attachment 35 in convergent relationship with respect to the top wall. The funnel 60 also includes a tubular choke portion 62 integral with the body portion 61 and having a substantially circular transverse cross-section. The choke portion 62 is tapered toward its open end remote from the body portion 61 to facilitate the insertion of the funnel within the conduit C through which the line L is adapted to be passed. Refer-ring to FIGURE 7, it will be observed that the funnel 60 comprises an outermost corrugated layer 63 of resilient insulative material, such as rubber or a suitable plastic, and an innermost spirally arranged layer 64 of coiled resilient insulative material, the individual coils of the spirally arranged inner layer 64 being received within complementary grooves formed by the corrugations provided in the outermost layer 63. The entrance adapter or funnel 60 is especially useful when it is desired to pass a line through a conduit in a relatively inaccessible location where space is at a premium. In such situations, the funnel 69 may be flexibly bent into a variety of shapes to enable the cartridge projectile 13 to be launched through the conduit, a feat which could not be accomplished without the funnel 619. The entrance adapter or funnel 60, being made from insulative material, can be used to successfully introduce the cartridge projectile 13 and its accompanying line package 30 into a conduit without danger of creating a fire hazard.

FIGURE 5 best illustrates the improved method of passing a guide line through a conduit embodied in the present invention, it being noted that as the line package 30 follows the cartridge projectile 13 in its path of travel through the conduit C, the line L is unwound from the rear end of the cylindrical roll 45 of the line package 30. In FIGURE 5, the rearwardly extending end of the line L is illustrated as being tied to the trigger guard of the gun 10 which is disposed outwardly of the conduit C, but it will be understood that this end of the line L may be held in the hand of the operator of the gun It) or otherwise secured to some object outside of the conduit C.

In certain installations, the path of travel of the cartridge projectile 13 terminates in an upward direction as it emerges from a conduit. Means are therefore provided to catch the cartridge projectile 13 as it emerges from the opposite end of the conduit C so as to prevent the cartridge projectile 13 from dropping back into the con duit C. The latter event could otherwise occur when the forward thrust derived from the gaseous substance contained in the cartridge projectile 13 diminishes because of the dissipation of the gases. Even when the forward thrust on the cartridge projectile 13 continues unabated after its emergence from the conduit C, an overhanging obstruction could deflect the cartridge projectile 13 backward into the conduit C unless some means for catching the cartridge projectile 13 is provided. In FIGURE 8, this catcher means 70' comprises an enlarged conical cup portion 71 having an open end adapted to be disposed around the end of conduit C from which the cartridge projectile 13 is adapted to emerge. The catcher 70 further includes a restrictor portion 72 integral with the enlarged conical cup portion 71. The restrictor portion 72 is also conical in shape, it being noted that the degree of taper incident in the enlarged conical cup portion 71 is substantially greater than that in the restrictor portion 72. As shown in FIGURE 9, the restrictor portion 72 includes a central bore 73 tapering toward the open end of the restrictor portion 72 remote from the enlarged conical cup portion 71. The diameter of the tapered bore 73 decreases to such an extent that the cartridge projectile 13 is unable to pass completely therethrough in its flight through the catcher 70. The cartridge projectile 13 is etfectively wedged in the restrictor portion 72, being trapped in the tapered bore 73 by increasing frictional engagement with the wall surface defining bore 73. The flight of the cartridge projectile 13 is therefore arrested and it is held within the restrictor portion 72 of the catcher 70 in trapped, wedged relationship. The catcher 70 comprises an outer corrugated layer 74 of resilient insulative material, such as rubber or suitable plastic, and an inner spirally arranged layer 75 having individual coils of resilient insulative material matingly received within grooves defined by the corrugations provided in the outer layer 74 in the same manner previously described with respect to the conduit entrance adapter or funnel 60. The insulation material from which the catcher 70 is made provides an important safety feature in that it prevents the formation of sparks upon the striking of the cartridge projectile 13 against the bore-defining surfaces of the catcher 70. The catcher 70 of insulative material therefore permits the practice of the method of passing a line through a conduit herein described in locations where safety precautions against fires or explosions must be given above normal attention.

Sometimes, the conduit C through which the cartridge projectile 13 is to be projected has a diameter larger than the longitudinal extent of the cartridge projectile 13. Such a situation is presented in FIGURE 10. Thus, should the cartridge projectile 13 strike the wall of the conduit C because of an angular bend therein or for any other reason, there would be nothing to prevent the cartridge projectile 13 from being deflected in such a manner as to reverse its direction of movement through the conduit C. Upon this event occurring, the cartridge projectile 13 would be likely to emerge from the same end of the conduit C into which it had been fired, resulting in damage to the gun and its associated parts if still adjacent this end of the conduit C, or, in the alternative, possible injury to the operator of the gun 10 should the gun have been removed. To overcome this problem, the present invention contemplates the use of a nose cone 80 to increase the effective length of the cartridge projectile 13 and to make it greater than the diameter of the conduit C, thereby preventing the cartridge projectile 13 from reversing its direction of movement in the conduit C, regardless of any deflection of the cartridge projectile 13 by the interior wall surface of the conduit C. The nose cone 80 is made of a resilient material, such as rubber or a suitable plastic, and comprises an elongated cylindrical tubular body portion 81 having an open end adapted to snugly receive the forward end of the cartridge projectile 13 with a friction fit and a conical tip 82 which closes the opposite end of the cylindrical body portion '81. When the nose cone 80 has been installed on the cartridge projectile 13 in the manner illustrated in FIG- URE 10, the cartridge projectile 13 may be fired through a conduit C possessing a relatively large diameter without fear of the cartridge projectile 13 reversing its direction of movement through the conduit C.

In practicing the improved method disclosed herein, the gun 10 is first cocked, as shown in FIGURE 1, and the launching attachment 35 is secured to its barrel 14. The cartridge projectile 13 containing a gaseous propellant therein is then placed within the upper barrel member 36 of the launching attachment 35, while the line package 30 secured thereto is placed within the lower barrel member 37 and the end of the line extending from the rear end thereof is tied to the trigger guard of the gun 10. The entrance adapter or funnel 60 is then forced into position about the launching attachment 35 in the manner illustrated in FIGURE 4 and the choke portion 62 of the funnel 60 is inserted in the conduit C through which the guide line L is to be passed. The operator then pulls the trigger 11 of the gun 10 to release the plunger 12 so that its firing pin 22 may puncture the rear end of the cartridge projectile 13 to actuate the same by permitting the gases contained therein to escape. Upon the escape of these gases, the cartridge projectile 13 is thrust forwardly out of the launching attachment 35 through the funnel 60 into the conduit C and pulls the line package 30 with it as it travels through the conduit C, the line L trailing from its rear end and attached to the trigger guard of the gun 10 unwinds from the cylindrical roll 45 beginning with the innermost winding disposed adjacent the longitudinal axis of the cylindrical roll 45 and unwinding outwardly. This arrangement, wherein the line package 30 follows close behind the cartridge projectile 13 while playing out the line L as it moves forwardly, substantially reduces the frictional drag of the line L on the cartridge projectile 13 tending to diminish its forward thrust developed by the escape of the gases through its punctured rear end. Thus, the cartridge projectile 13 is permitted to successfully complete its passage through the conduit C drawing the line package 30 thereafter for laying the guide line L therefrom through the conduit C even though there may be numerous bends in the conduit C and the conduit C may be unusually long.

The present method also contemplates the capture of the cartridge projectile 13 as it emerges from the opposite end of the conduit C by a catcher 70 in the manner previously described, this catcher 70 being especially useful where the path of travel of the cartridge projectile 13 as it emerges from the conduit C terminates in an upward direction. As a further step in the method herein disclosed, a nose cone may be installed on the forward end of the cartridge projectile 13 in instances where the cartridge projectile 13 is to be fired through a conduit having a diameter sufiiciently large to permit the cartridge projectile 13 to reverse its direction of movement therein. The installation of the nose cone 80 on the cartridge projectile 13 eifectively increases the longitudinal extent of the cartridge projectile 13 to prevent such an occurrence.

I have therefore disclosed an improved method of passing a guide line through a conduit for the purpose of subsequently drawing a relatively rigid line or similar elongated article therethrough, wherein the line is wound in a cylindrical roll comprising a line package which closely follows a cartridge projectile in its path of travel through the conduit, While the line from the trailing end thereof is unwound. This practice substantially reduces the frictional resistance or drag occasioned by the prior practice of pulling a line through the conduit by attaching one end to a projectile forced through the conduit by a propelling pressure. There have also been disclosed several attachments for a hand tool or gun which facilitate the performance of this improved method.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A method of passing a line through a conduit comprising the steps of assembling a launching attachment on the barrel of a gun, inserting a cartridge projectile and a line package into respective compartments of the launching attachment, attaching one end of the line in the line package to the cartridge projectile, securing the opposite end of the line in the line package to an object outside of the conduit, successively but separately introducing the cartridge projectile and the line package into one end of the conduit by firing the gun to thrust the cartridge projectile forwardly through the conduit while pulling the line package thereafter and unwinding the line from the trailin-g end of the line package in response to its movement away from the object, and guiding the projectile and the line package attached thereto through the conduit by the internal wall surface of the conduit to lay the line unwound from the line package in the length of the conduit.

2. A method of passing a line through a conduit as defined in claim 1, further including the step of positioning a conduit entrance adapter around the launching attachment and within the end of the conduit into which the cartridge projectile and line package are to be introduced prior to the firing of the gun.

3. A method of passing a line by means of a projectile through a conduit having a diameter larger than the length of the projectile comprising the steps of attaching one end of the line to the projectile, securing the opposite end of the line to an object outside of the conduit, increasing the elfective longitudinal extent of the projectile to a length greater than the diameter of the conduit, firing the projectile through the conduit to pull the line thereafter in response to movement of the projectile away from the object, and guiding the projectile through the conduit by the internal Wall surface of the conduit to lay the line in the length of the conduit.

4. A method of passing a line through a conduit comprising the steps of attaching one end of the line in a line package to a projectile, securing the opposite end of the line in the line package against movement, successively but separately introducing the projectile and the line package into one end of the conduit by firing the projectile through the conduit to pull the line package thereafter While unwinding the line from the trailing end of the line package in the length of the conduit in response to movement of the line package away from the secured end of line, and guiding the projectile and the line package attached thereto through the conduit by the internal wall surface of the conduit to lay the line unwound fro-m the line package in the length of the conduit.

5. A method of passing a line through a conduit comprising the steps of attaching one end of the line in a line package to a projectile, securing the opposite end of the line in the line package against movement, successively but separately introducing the projectile and the line package into one end of the conduit 'by firing the projectile through the conduit to pull the line package thereafter while unwinding the line from the trailing end of the line package in the length of the conduit in response to movement of the line package away from the secured end of line, guiding the projectile and the line package attached thereto through the conduit by the internal wall surface of the conduit to lay the line unwound from the line package in the length of the conduit, and catching the projectile as it emerges from the other end of the conduit.

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